SEATTLE — Juan Soto’s milestone home run came with a dash of reality.

As he finished off his home run tour of all 30 active ballparks in the Yankees win over the Mariners on Tuesday night, Soto sent a reminder of what’s coming this offseason.

“So many different ballparks, so many different dimensions,” Soto said before the Yankees’ 2-1, playoff-clinching win over Seattle in 10 innings on Wednesday night. “I just want to get all of them checked [off]. What a best way to go into free agency with homers in all 30 ballparks, checking my list.”

The Yankees hope there will be plenty more to come from Soto in their uniform, though they are guaranteed only the remaining 11 games of the regular season and however long they last in October.

After that — despite Hal Steinbrenner saying in May he wanted to explore an extension with the superstar, which always seemed unlikely to come to fruition — Soto is set to hit the open market, where his price tag is expected to soar over $500 million.

The 25-year-old’s two-run shot off Bryan Woo marked the 40th of his season (extending his single-season high) and the 200th of his career.

And yet it was the third achievement — hitting a homer in all 30 ballparks — that Soto indicated was the most meaningful to him.

It will surely be one of the many selling points for Soto and his agent, Scott Boras, this offseason that he can hit anywhere.

“It’s one of the goals I’ve really put [thought] into in my career,” said Soto, who had stated it as a goal in spring training to go deep in all 30 parks (he had five remaining before this season). “When I got to this year, being in the American League now, I was like, ‘I have a really good chance to do it.’ So right when I hit it, I was like, ‘Oh finally, I got the last one.’ ”

The Yankees seem to have made a strong impression on Soto, especially as he enjoys the luxury of hitting in front of Aaron Judge, but money will talk loudest at the end of the day.

In the meantime, Soto who went 1-for-2 with two walks in Wednesday’s win, made more history with Judge on Tuesday.

The duo — with Judge at 53 home runs — became only the third set of Yankees teammates ever to hit 40 home runs in the same season, joining Roger Maris and Mickey Mantle (1961), and Babe Ruth and Lou Gehrig (1927, 1930, 1931).

“Since I got here in spring training, my goal was to put my name close to those history books and be part of it,” Soto said. “Now being up there and being with those guys, it’s a great experience. It feels really cool.”

Soto reached 200 homers for his career in his 926th career game and 3,247th career at-bat.

Others have reached the milestone in fewer games and at-bats, but Soto (at 25 years and 328 days old) became the seventh-youngest player to ever do it — trailing only Mel Ott, Eddie Matthews, Albert Pujols, Jimmie Foxx, Mickey Mantle and Alex Rodriguez.

“It’s amazing,” Judge said. “Forty homers, hit the 200th, hit every ballpark. That’s tough to do when I feel like he just got into this game. But what a career he’s having, what a year he’s having. Definitely looking forward to more of that the rest of this year and beyond.”

Whether Judge will get a front-row view for it in the “beyond” remains to be seen, but for now, the Yankees are just trying to enjoy Soto’s presence and take advantage of it as they chase down a division title and more.

“You’re always just like, ‘Man, this guy’s just 25. Maybe he’s just scratching the surface of who he is,’ ” manager Aaron Boone said. “In a lot of ways, he’s not necessarily even entered his prime. Maybe he’s entering it now. I think we all would acknowledge that we’re watching a really special hitter.”